In a vehicle transmission such as found in conventional automobiles, normal maintenance and service requires removal of the transmission pan which is usually fastened at its peripheral mounting flange by a plurality of bolts to the bottom of the transmission housing. For example, the pan must be removed to repair or to inspect the transmission or simply to change the transmission fluid contained within the transmission as is commonly periodically done for preventive maintenance purposes. Unfortunately, most automatic transmissions today are not provided with drain plugs for removal of the fluid retained within the transmission by the pan so that the transmission cannot be emptied of fluid without removing the pan. Removal of the pan by a service mechanic has always been messy, time consuming and difficult, and harmful when the fluid is hot, particularly because the quantity of fluid is greater than the capacity of the transmission pan and separation of the pan from the transmission housing results immediately in the fluid flowing through the gap formed between the pan and housing by such separation. This has been a long standing problem confronting service mechanics.
It is well known to persons acquainted with automobile maintenance that the generally accepted method of removing a transmission pan is to place a large tub or basin on the floor or on a pedestal beneath the transmission and then to loosen the bolts with a suitable tool so that the pan will tip slightly at one corner hopefully to drain thereat the fluid from the pan more or less in a stream. However, upon loosening of the pan bolts and separation of the pan from the housing, the fluid oftentimes before such tipping can be accomplished will leak through the gap formed between the pan and housing and/or through the bolt holes in the pan mounting flange causing fluid, which may be hot, to run down the arms of the mechanic and/or to squirt beyond the peripheral extent of the tub onto the floor. Moreover, if the tub is mispositioned, considerable fluid may be drained onto the floor before the service mechanic can remedy the problem.
Only after the transmission housing has drained but for the fluid contained within the pan, which may take several minutes, the bolts are then completely removed preferably while an assistant holds the pan to prevent the same from falling into the basin and to prevent the fluid therein from spilling. As the pan often is slippery and because the assistant normally must reach over the basin to hold and remove the pan, it is not unknown for the pan to slip from the assistant's hands and either drop into the basin causing the fluid therein to splash or drop to the floor causing the fluid contained in the pan to spill onto the floor.
Thus, it can be seen that such known method is not only messy and difficult, but is time consuming requiring the bolts to be loosened in a special sequence for draining and then later removed only after considerable delay for allowing the transmission fluid to drain from the transmission. Moreover, such method preferably requires two persons, one to remove the bolts while the other holds the pan to prevent the same from dropping. Also, the mechanic may be burned when the hot fluid contacts his skin.